1 Magnetic accumulation and extraction of Cd(II), Hg(II) and Pb(II) by a 2 novel nano-Fe 3 O 4 -coated-dioctylphthalate-immobilized- 3 hydroxylamine 4 Mohamed E. Mahmoud a, * Q1 , Amr A. Yakout a, b,1 , Kholoud H. Hussein a, 2 , 5 Maher M. Osman a, 3 6 a Faculty of Science, Chemistry Department, Alexandria University, P.O. Box 426, Alexandria 21321, Egypt 7 b Department of Chemistry-Faculty of Science, North Jeddah – King AbdulAziz University, Jeddah, Saudi Arabia A R T I C L E I N F O Article history: Received 27 December 2014 Received in revised form 16 March 2015 Accepted 25 March 2015 Keywords: Magnetic accumulation Removal Heavy metals Hydroxylamine Magnetic nano-iron oxide A B S T R A C T A magnetic nano-sorbent was synthesized via direct surface impregnation of dioctyl phthalate (Dop) on magnetic nano-iron oxide (nano-Fe 3 O 4 ) for the formation of (nano-Fe 3 O 4 -Dop). The produced material was further functionalized with nitrogen and oxygen donor atoms by surface immobilization of hydroxylamine for the formation of a novel magnetic nano-sorbent (nano-Fe 3 O 4 -Dop-HA). This was identified using SEM, HR-TEM, TGA, FT-IR and surface area determination. The average particle size was found in the range of 5–16 nm based on the HR-TEM analysis. The incorporated selectivity was examined for removal of Cd(II), Hg(II) and Pb(II) from aqueous solutions by the static and dynamic techniques. Nano-Fe 3 O 4 -Dop-HA was identified by high Hg(II) uptake capacity values (1433.3–1633.3 mmol g 1 in pH 1.0–7.0) compared to Cd(II) and Pb(II). The contributions of pH, contact time and nano-sorbent dosage, initial metal ion concentration and interfering ions on the magnetic solid phase extraction by nano- Fe 3 O 4 -Dop-HA were also studied and optimized. The potential applications of nano-Fe 3 O 4 -Dop-HA for removal of Cd(II), Hg(II) and Pb(II) from industrial wastewater, seawater and drinking tap water samples were successfully accomplished using a multistage micro-column technique. ã 2015 Published by Elsevier Ltd. 8 Introduction 9 Pollution of surface water and ground water is now known as a 10 worldwide critical issue. This problem has resulted due to high 11 population growth and rapid developments in industrialization [1]. 12 Persisting contaminants and pollutants in water and wastewater 13 may include various components such as heavy metals, organic and 14 inorganic derivatives as well as other complex compounds [2]. 15 Consequently, it is necessary to prevent or control the harmful effects 16 of these pollutants in order to improve the human living environ- 17 ments [3,4]. Direct applications of treatment processes are generally 18 controlled by several factors including processing efficiency, 19 operational method, economical benefits and energy requirements. 20 Recently, nano-materials have been proposed in various disciplines 21 as efficient, cost effective, environmental friendly alternative to 22 existing treatment materials from the standpoints of both resource 23 conservation and environmental remediation [5]. Applications of 24 nano-materials for wastewater treatment have been focused on 25 magnetic nano-materials [6], carbon nano-tubes [7], activated 26 carbon [8] and nano zero-valent iron [9] as well as other metal 27 oxides [10–14]. Among these materials, magnetic iron oxide (NMs) 28 exhibited good capacity for treatment of large volumes of 29 wastewater as well as ability to use in magnetic removal of heavy 30 metal from different matrices [15]. 31 Iron oxides are existing in nature in several forms including 32 magnetite (Fe 3 O 4 ), maghemite (g-Fe 2 O 3 ) and hematite (a-Fe 2 O 3 ) 33 as the most common forms [16]. Iron oxide nano-particles have 34 been widely used in water treatments due to their important 35 properties such as nano-size range, high surface area to volume 36 ratios and super-magnetism [17] as well their easy synthesis, 37 possible surface modification and ability to control [18]. In 38 addition, iron oxides are characterized by low toxicity, chemically 39 inertness and biocompatibility [19]. It has been reported that the 40 preparation method and surface coating medium can play a major 41 role in determining the size distribution and morphology, 42 magnetic properties and surface chemistry of these nano- * Corresponding Q2 author. Tel.: +20 140933009; fax: +20 33911794. E-mail addresses: memahmoud10@hotmail.com (M.E. Mahmoud), AAYAKOUT@yahoo.com (A.A. Yakout), kholoudhamza135@yahoo.com (K.H. Hussein), Maher_Osman@yahoo.com (M.M. Osman). 1 Tel.: +20 1001609201; fax: +20 33911794. 2 Tel.: +20 1119242901; fax: +20 33911794. 3 Tel.: +20 1111355544; fax: +20 33911794. http://dx.doi.org/10.1016/j.jece.2015.03.024 2213-3437/ ã 2015 Published by Elsevier Ltd. Journal of Environmental Chemical Engineering xxx (2015) xxx–xxx G Model JECE 605 1–9 Please cite this article in press as: M.E. Mahmoud, et al., Magnetic accumulation and extraction of Cd(II), Hg(II) and Pb(II) by a novel nano- Fe 3 O 4 -coated-dioctylphthalate-immobilized-hydroxylamine, J. Environ. Chem. Eng. (2015), http://dx.doi.org/10.1016/j.jece.2015.03.024 Contents lists available at ScienceDirect Journal of Environmental Chemical Engineering journal homepage: www.else vie r.com/locat e/jece